1. Field of the Invention
The present invention relates to the technology that is associated with the image processing utilized in a position detection etc. The present invention relates the technology that is associated with a pattern matching method or a pattern search of searching the predetermined pattern image, which is registered previously, from an input image as search objects while using a pyramid structure search. More particularly, the present invention relates to a pattern matching method of displaying set parameters necessary for a pyramid structure search, an image detecting device for executing the pattern matching, and a computer-readable medium inducing a program for executing the pattern machining.
2. Description of the Related Art
The image processing is utilized in various fields such as the manufacture, the packaging, etc. of electronic parts in the factory. In particular, the pattern matching for searching a predetermined pattern from an image data obtained by an imaging camera etc. is utilized in applications such as the positioning, etc. An example of the pattern matching is shown in FIG. 8. An input image shown in FIG. 8 is constructed by a matrix arrangement in which an area is divided into a plurality of pixels G. As shown in FIG. 8, the pattern matching is applied to the input image area SA1 while moving a previously-registered pattern image RF1 to detect a coordinate at which a detected image OB is to be positioned.
If the practical use is taken into consideration, the higher speed is indispensable to the pattern matching. In this pattern matching, an enormous process time is required if a search for investigating closely the image data as the processed objects in all areas is carried out. Therefore, any means for reducing the process time is needed. In particular, since an approach that is called a pyramid structure search divides the process into plural stages to execute it, such approach is utilized as the approach that can reduce the required process time.
The pyramid structure search is set forth in Japanese Patent Publication (KOKOKU) Hei. 7-37893, for example. In the pyramid structure search, an image serving as the object of the pattern matching method is compressed, then a coarse search processing is applied to the compressed image, and then a coordinate position at which a desired pattern is present is detected. Then, a detailed search processing is carried out around the neighborhood of the detected coordinate to detect the more precise position. In this manner, the rough position is identified according to the coarse search and then the detailed search is carried out in the identified range based on this result. Thus, only the necessary portion can be sequentially investigated closely not to execute the detailed search over the overall image. As a result, the total process time can be reduced.
In the pyramid structure search, the processing speed has the trade-off relation with the processing precision. Normally there is such a tendency that, if the number of search hierarchies is increased, the processing speed can be accelerated but the processing precision is lowered. Thus, the number of hierarchies suitable for the individual image processing must be set. Further, a plurality of parameters required for other operations must also be set. It is difficult to cause the user to set these plural parameters completely. Therefore, if the pattern matching is carried out by using the pyramid structure search in the related art, the required process time is calculated by the computer, or the like on an image detecting device side and also the parameters that are supposed as the optimum are decided automatically.
However, according to this method, the image processing is automatically fixed only by the parameters that are calculated in the device side, and therefore it is impossible to adjust/change respective settings on the user side. In many image detecting devices, a group of parameters that are calculated automatically is decided uniquely and these set contents are fixed. Accordingly, it is impossible to change the set contents on the user side, and thus the margin of setting is not given to the user. The set contents may be displayed to inform the user of such contents, or may be automatically set not to inform the user of the parameter values. In the case where the user is not informed of the information about the parameters, such user cannot confirm the information to achieve the change even if the user tries to change the set contents.
In addition, the values that are automatically calculated in this manner are not always the optimum parameter values that can respond to the user's application situation. Particularly, in the pattern matching method, the calculation of the parameters is carried out based on a predetermined image that is previously registered. For this reason, the optimum parameters are not always calculated so as to respond flexibly to various changes of the image data that are actually input.
Moreover, in the pattern matching, the user wishes to change a part or all of the set contents in response to the case where the reflection factor of the examined object is poor, the generation of noise, the variation in illumination, etc. For example, sometimes the user wishes to adjust the set contents according to the result after the pattern matching is carried out by using the set parameter values. In order to satisfy such request, there is the necessity that a group of calculated parameter candidates should be displayed to the user to permit the change of respective parameters. In addition, if not only a group of parameter candidates is merely displayed but also such an environment can be provided that plural groups of parameter candidates are displayed such that the user can select the optimum set in response to his or her desire, the user can combine the appropriate values mutually, or the like, the pattern matching can be used more conveniently.